Presentation on theme: "Chapter 5 Operational Amplifier. Introduction A typical op amp: a) pin configuration, b) circuit symbol An op amp is an active circuit element designed."— Presentation transcript:
Introduction A typical op amp: a) pin configuration, b) circuit symbol An op amp is an active circuit element designed to perform mathematical operation of addition, subtraction, multiplication, division, differentiation, and integration.
Terminal Voltage and Currents Vd=V2-V1 (differencial input) Vo=AVd=A(V2-V1) A: gain (open-loop voltage gain)
Actual op amp: Ri(very large); Ro(very small); A(very large) Idealization: Ri=> ; Ro=>0 ; A=> As Vo is limited, we can get from Vo=A(V2-V1) that: V2=V1 As Ri=> , we can get i 1 =0, i 2 =0 i1i1 i2i2
Ideal op amp 1)i1=0, i2=0 ; 2)V1=V2 Ideal op amp model i1 i2
P.P.5.10As a voltage follower, v a = v 1 = 2V where v a is the voltage at the right end of the 20 k resistor. As an inverter, v b = Where v b is the voltage at the right end of the 50k resistor. As a summer v 0 = = [6 - 15] = 9V